FIG. 17 shows an entire image of a package including a conventional transceiver module for optical communications. The entire package is configured with optical transmission line 41, CAN Package for transmission (hereafter “package”) 24, and CAN Package for reception (hereafter “package”) 25. Fixing jig 42 secures optical transmission line 41. Packages 24 and 25 are mounted on printed circuit board (hereafter “board”) 34, and enclosed in package 21. The name CAN Package comes from the use of a metal can for the package. Fixing jig 42 and adapter 21A of package 21 are fitted, and the optical axis of optical transmission line 41 and optical axes of packages 24 and 25 are aligned by means of this modular structure.
FIG. 18 shows board 34 enclosed in package 21. Packages 24 and 25, semiconductor device 45, and passive element 26 are mounted on board 34.
FIG. 19 is a sectional view of FIG. 18 taken along Line A–A′ on board 34 including the center axes of packages 24 and 25. Light-emitting device 29 is mounted inside package 24, and sealing material 33 hermetically seals this package 24. In addition, optical component 27 such as lens or window is installed in package 24. The light emitted from light-emitting device 29 enclosed in package 24 passes through optical component 27 and enters optical transmission line 41 whose optical axis is aligned by the modular structure. This enables the module to transmit signals.
In the same way, light-receiving device 30 is mounted inside package 25, and sealing material 33 hermetically seals this package 25. In addition, optical component 28 such as lens or window is installed in package 25. The light output from transmission line 41 of the reception side whose optical axis is aligned by the modular structure passes through optical component 28 installed in package 25, and arrives at light-receiving device 30. This enables the module to receive signals. This type of package, including a transceiver module for optical communications, is disclosed in Japanese Unexamined Patent Publication No. H11-345987.
In the above structure, however, the alignment of optical axes of light-emitting device 29 and light-receiving device 30, and respective optical components 27 and 28 depends on packages 24 and 25. Moreover, the alignment of the optical axes of light-emitting device 29, light-receiving device 30, and optical components 27 and 28 and the optical axis of optical transmission line 41 depends on the modular structure of fixing jig 42 and adapter 21A of package 21. For each alignment, the optical axes need to be separately aligned. Furthermore, the size of packages 24 and 25 limits downsizing and height reduction because packages 24 and 25 are mounted on board 34.